Electric heater device

ABSTRACT

An electric heater device includes: a plurality of pipes stacked with each other through a predetermined clearance, a fluid flowing inside the plurality of pipes; a heating element that emits heat by being energized; and an electronic component module including an electronic component different from the heating element. The heating element and the electronic component module are disposed in the clearance between the plurality of pipes.

CROSS REFERENCE TO RELATED APPLICATION

This application is based on Japanese Patent Application No. 2018-75621 filed on Apr. 10, 2018, the disclosure of which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

The present disclosure relates to an electric heater device.

BACKGROUND ART

An electric heater device includes pipes stacked for flowing water with a predetermined gap, a heating element, and a casing for housing the pipes and the heating element. The pipes and the heating element are made in tight contact. Further, a temperature sensor is disposed to detect the temperature of water flowing in the pipe. In the electric heater device, heat emitted from the heating element is transferred to the water flowing inside of the pipe, whereby the water is heated.

SUMMARY

According to an aspect of the present disclosure, an electric heater device includes: a plurality of pipes stacked with each other through a predetermined clearance, a fluid flowing inside the plurality of pipes: a heating element that emits heat by being energized; and an electronic component module including an electronic component different from the heating element. The heating element and the electronic component module are disposed in the clearance between the plurality of pipes.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic plan view illustrating an electric heater device according to a first embodiment.

FIG. 2 is a schematic front view illustrating the electric heater device of the first embodiment.

FIG. 3 is a schematic front view illustrating an electronic component module of the first embodiment.

FIG. 4 is a schematic rear view illustrating the electronic component module of the first embodiment.

FIG. 5 is a block diagram illustrating an electrical configuration of the electric heater device of the first embodiment.

FIG. 6 is a schematic plan view illustrating an electric heater device according to a modification of the first embodiment.

FIG. 7 is a schematic plan view illustrating an electric heater device according to another modification of the first embodiment.

FIG. 8 is a block diagram illustrating an electrical configuration of an electric heater device according to a second embodiment.

DETAILED DESCRIPTION

An electric heater device including a tubular laminate in which pipes are stacked for flowing water with a predetermined gap, a heating element arranged in the gap, and a casing for housing the tubular laminate and the heating element. A thick portion is formed in the casing to protrude from an inner surface of an external wall of the casing. A pressing member is provided in the casing to press the tubular laminate against the thick portion in order to make the pipes and the heating element in tight contact. Further, a temperature sensor is disposed on the thick portion to detect the temperature of water flowing in the pipe. In the electric heater device, heat emitted from the heating element is transferred to the water flowing inside of the pipe, whereby the water is heated.

In order to install the temperature sensor, it is necessary to form the thick portion in the housing. This is a factor leading to enlargement of the casing. The present disclosure has been made in view of such circumstances, and an object thereof is to provide an electric heater device in which a casing can be downsized.

According to an aspect of the present disclosure, an electric heater device includes: a plurality of pipes stacked with each other through a predetermined clearance; a fluid flowing inside the plurality of pipes; a heating element that emits heat by being energized; and an electronic component module including an electronic component different from the heating element. The heating element and the electronic component module are disposed in the clearance between the plurality of pipes.

Accordingly, there is no need to separately provide an installation space for the electronic component outside the tubular laminate, since the electronic component module is disposed in the clearance between the pipes. Therefore; it is possible to downsize the electric heater device.

Hereinafter, embodiments will be described with reference to the drawings. For easy understanding, the same reference numerals are attached to the same elements among the drawings where possible, and redundant explanations are omitted.

First Embodiment

An electric heater device 10 of a first embodiment will be described with reference to FIG. 1. The electric heater device 10 is used, for example, to raise the temperature of a heater core by electrically heating water circulating through the heater core in an air conditioner for a vehicle. It is possible to raise the temperature of air blown into the passenger compartment by raising the temperature of the heater core, so that the heating of the passenger compartment becomes possible. In the electric heater device 10 of the present embodiment, water is used as a fluid to be heated.

As shown in FIG. 1, the electric heater device 10 includes a pipe stacked body 20, plural heating elements 30, a housing 40, a pressing member 50, a plate 60, and an electronic component module 70. The pipe stacked body 20 includes plural flat pipes 21, through which water flows, stacked with each other through a predetermined clearance in the Y-axis direction. Hereinafter, one direction in the Y-axis direction is referred to as “Y1 direction”, and the opposite direction is referred to as “Y2 direction”. Further, the longitudinal direction of the pipe 21 is referred to as “X-axis direction”. One direction in the X-axis direction is referred to as “X1 direction”, and the opposite direction is referred to as “X2 direction”. Further, as shown in FIG. 2, a direction perpendicular to both the X-axis direction and the Y-axis direction is referred to as Z-axis direction. One direction in the Z-axis direction is referred to as “Z1 direction”, and the opposite direction is referred to as “Z2 direction”.

An end portion of each pipe 21 in the X1 direction is connected to a distribution pipe 22 extended in the Y-axis direction. The end portions of the pipes 21 in the X1 direction communicate through the distribution pipe 22. An end portion of each pipe 21 in the X2 direction is connected to a collecting pipe 23 extended in the Y-axis direction. The end portions of the pipes 21 in the X2 direction communicate through the collecting pipe 23.

One end portion of the distribution pipe 22 in the Y2 direction is connected to an inflow port 61 formed in the plate 60, One end portion of the collecting pipe 23 in the Y2 direction is connected to an outflow port 62 formed in the plate 60. In the pipe stacked body 20, water flowing into the inflow port 61 is distributed into the respective pipes 21 via the distribution pipe 22, and water flows through the inside of each pipe 21 in the X2 direction. The water flowing through each pipe 21 is collected in the collecting pipe 23 and then flows out from the outflow port 62.

A first pipe 21 a is located the nearest to the inflow port 61 and the outflow port 62, among the plural pipes 21, in the Y2 direction, and a second pipe 21 b is positioned adjacent to the first pipe 21 a in the Y1 direction. The electronic component module 70 is arranged in the clearance formed between the first pipe 21 a and the second pipe 21 b. The heating elements 30 are disposed in the other clearance s between the pipes 21. Each of the electronic component module 70 and the heating element 30 is sandwiched by the pipes 21.

The heating element 30 is made of, for example, a ceramic heater element manufactured by sintering after placing a resistor inside, or a PTC element, and generates heat by being energized. The heating element 30 has an outer surface 32 in the Z-axis direction, and a terminal 31 is disposed on the outer surface 32. The terminal 31 is electrically connected to the substrate 80 arranged to face the pipe stacked body 20 in the Z-axis direction. The heating element 30 generates heat based on electric power supplied through the substrate 80. The heat generated from the heating element 30 is transmitted to the pipe 21, whereby the water flowing inside each pipe 21 is heated.

The electronic component module 70 includes electronic components different from the heating elements 30, such as a switching element 71, a first temperature sensor 72, and a second temperature sensor 73. A terminal 74 is provided on the outer surface 75 of the electronic component module 70 in the Z-axis direction. The terminal 74 is electrically connected to the substrate 80.

The switching element 71 and the first temperature sensor 72 are arranged on the outer surface 76 of the electronic component module 70 in the Y2 direction. The outer surface 76 of the electronic component module 70 is in contact with the first pipe 21 a. As shown in FIG. 3, the switching elements 71 are arranged in the X-axis direction at substantially the center of the outer surface 76 of the electronic component module 70. The switching element 71 is formed of an IGBT, a MOSFET, or the like. The switching element 71 is a part of a driving circuit that drives the heating element 30, and is turned on/off to supply/stop electric power to the heating element 30. The first temperature sensor 72 is disposed at an end portion of the outer surface 76 of the electronic component module 70 in the X1 direction. As shown in FIG. 1, the first temperature sensor 72 is located at a contact portion P1 on the first pipe 21 a, the most upstream side in the flow direction of water, where the electronic component module 70 is in contact with the first pipe 21 a, In the present embodiment, the contact portion P1 corresponds to a first contact portion. The first temperature sensor 72 detects the temperature of the first pipe 21 a in contact with the contact portion P1 and outputs a signal corresponding to the detected temperature.

The second temperature sensor 73 is disposed on the outer surface 77 of the electronic component module 70 in the Y1 direction. The outer surface 77 of the electronic component module 70 is in contact with the second pipe 21 b. As shown in FIG. 4, the second temperature sensor 73 is disposed at an end portion of the outer surface 77 of the electronic component module 70 in the X2 direction. As shown in FIG. 1, the second temperature sensor 73 is located at a contact portion P2 on the second pipe 21 b, the most downstream side in the flow direction of water, where the electronic component module 70 is in contact with the second pipe 21 b. In the present embodiment, the contact portion P2 corresponds to a second contact portion. The second temperature sensor 73 detects the temperature of the second pipe 21 b in contact with the contact portion P2 and outputs a signal corresponding to the detected temperature.

As shown in FIG. 1, the housing 40 is made of metal member, and has a square box shape. The pipe stacked body 20, the heating element 30, the pressing member 50, the electronic component module 70, and the substrate 80 are housed inside the housing 40. An opening 42 is formed in the side wall 41 of the housing 40 in the Y2 direction. The plate 60 is inserted in the opening 42. As shown in FIG. 2, the plate 60 is integrally assembled to the housing 40 with a bolt 64, thereby closing the opening 42 of the housing 40.

As shown in FIG. 1, the inflow port 61 and the outflow port 62 are formed on the outer surface of the plate 60 to protrude in the Y2 direction. Each end of the distribution pipe 22 and the collecting pipe 23 is inserted into the plate 60 from the outer surface of the plate 60 in the Y1 direction. One end of the distribution pipe 22 communicates with the inflow port 61 through a flow path (not shown) formed inside the plate 60. Similarly, one end of the collecting pipe 23 communicates with the outflow port 62 through a flow path (not shown) formed inside the plate 60.

A protruding portion 63 is formed to protrude from the outer surface of the plate 60 in the Y1 direction. The tip end of the protruding portion 63 is in contact with the first pipe 21 a. The pipe stacked body 20 is pressed against the protruding portion 63 by the pressing member 50. Specifically, the pressing member 50 is disposed between the housing 40 and the pipe 21 disposed at the endmost area in the Y1 direction in the pipe stacked body 20. The pressing member 50 is made of a leaf spring or the like and presses the endmost pipe 21 in the Y2 direction by the elastic force thereof in the pipe stacked body 20. The pipe stacked body 20 is pressed against the protruding portion 63 of the plate 60 by the elastic force of the pressing member 50. As a result, the pipes 21 and the heating elements 30 can be made in tight contact, so that it is possible to enhance the thermal conductivity therebetween.

Next, an electrical configuration of the electric heater device 10 will be described. As shown in FIG. 5, the electric heater device 10 further includes a controller 90 mounted on the substrate 80. In the present embodiment, the controller 90 corresponds to a calculator. The controller 90 switches on/off the switching element 71 based on the temperatures detected by the first temperature sensor 72 and the second temperature sensor 73. Thus, the temperature of the water flowing out from the outflow port 62 is controlled to have the target temperature by controlling the amount of heat generated by the heating element 30.

Specifically, the controller 90 detects the temperature of the first pipe 21 a in contact with the contact portion P1 of the electronic component module 70 based on the output signal of the first temperature sensor 72, Based on the temperature detected by the first temperature sensor 72, the controller 90 acquires information on the inflow temperature T1, which is the temperature of the water flowing into the pipe stacked body 20. Further, the controller 90 detects the temperature of the second pipe 21 b in contact with the contact portion P2 of the electronic component module 70, based on the output signal of the second temperature sensor 73. Based on the temperature detected by the second temperature sensor 73, the controller 90 acquires information on the outflow temperature T2, which is the temperature of the water flowing out from the pipe stacked body 20.

The controller 90 monitors, for example, whether or not the inflow temperature T1 is less than a predetermined temperature. When the inflow temperature T1 is equal to or higher than the predetermined temperature, the controller 90 determines that there is a possibility that the water boils when the water is further heated by the heating element 30, and stops the supply of power to the heating element 30, thereby stopping the heat generation by the heating element 30.

When the inflow temperature T1 is lower than the predetermined temperature, the controller 90 controls the heat generation amount of the heating element 30 based on the outflow temperature T2. Specifically, the controller 90 calculates the duty ratio based on the deviation between the outflow temperature T2 and the target temperature, and turns on/off the switching element 71 based on the calculated duty ratio, to control the amount of heat generated by the heating element 30.

According to the electric heater device 10 of the present embodiment described above, it is possible to obtain the following effects (1) to (3).

(1) The heating element 30 and the electronic component module 70 are arranged in the clearances between the pipes 21. The electronic component module 70 includes the electronic components different from the heating element 30, such as the switching element 71, the temperature sensors 72, 73. Accordingly, it is unnecessary to separately provide an installation space for the electronic components such as the switching element 71 and the temperature sensors 72, 73 outside the pipe stacked body 20, so the electric heater device 10 can be downsized.

(2) The electronic component module 70 has the first temperature sensor 72 disposed on the first contact portion P1 in contact with the first pipe 21 a. Since the first pipe 21 a is in contact with only the electronic component module 70, heat generated from the heating element 30 is hardly transmitted to the first pipe 21 a. In addition to this, since the first contact portion P1 is located in the vicinity of the distribution pipe 22, the temperature of the first contact portion P1 is substantially equal to the temperature of water flowing into the inflow port 61, in other words, the temperature of water before being heated by the heating element 30. Therefore, the first temperature sensor 72 can accurately detect the temperature of water before being heated by the heating element 30.

(3) The electronic component module 70 has the second temperature sensor 73 disposed on the second contact portion P2 in contact with the second pipe 21 b. Since the second pipe 21 b is in contact with the heating element 30, heat generated from the heating element 30 is transmitted to the second pipe 21 b. In addition, since the second contact portion P2 is located in the vicinity of the collecting pipe 23, the temperature of the second contact portion P2 is approximately equal to the temperature of water heated by the heating element 30, in other words, the temperature of water flowing out from the outflow port 62. Therefore, the second temperature sensor 73 can accurately detect the temperature of water heated by the heating element 30.

Modifications

A first modification of the electric heater device 10 of the first embodiment will be described. As shown in FIG. 6, in the electric heater device 10 of this modification, not only the second temperature sensor 73 but also the switching element 71 and the first temperature sensor 72 are disposed on the outer surface 77 of the electronic component module 70. That is, in the present modification, the first temperature sensor 72 is disposed at the first contact portion P1 on the most upstream side in the flow direction of water flowing through the second pipe 21 b, and the second temperature sensor 73 is disposed at the second contact portion P2 on the most downstream side in the flow direction of water flowing through the second pipe 21 b.

According to the first modification, the inflow temperature T1 can be detected by the first temperature sensor 72, and the outflow temperature T2 can be detected by the second temperature sensor 73. The electronic component module 70 is not limited to be located in the clearance the closest to the inflow port 61 and the outflow port 62. For example, as shown in FIG. 7, the electronic component module 70 may be located in the other clearance.

Second Embodiment

A second embodiment of the electric heater device 10 will be described. Hereinafter, differences from the electric heater device 10 of the first embodiment will be mainly described. As shown in FIG. 8, the electric heater device 10 of the present embodiment does not have the second temperature sensor 73, differently from the electric heater device 10 of the first embodiment. The controller 90 calculates the outflow temperature T2 based on the inflow temperature T1 detected by the temperature sensor 72.

Specifically, the electric heater device 10 has a voltage sensor 100 for outputting a signal corresponding to the voltage applied to the heating element 30, and a current sensor 110 for outputting a signal corresponding to the current flowing through the heating element 30. The controller 90 detects the voltage value V applied to the heating element 30 based on the output signal of the voltage sensor 100, and detects the current value I flowing through the heating element 30 based on the output signal of the current sensor 110. The controller 90 multiplies the voltage value V and the current value I, thereby obtaining the electric power W supplied to the heating element 30. Further, the controller 90 also obtains the integrated value of the current value I. Further, the controller 90 measures the energization time Ti, which is a time period during which electric power is supplied to the heating element 30. The controller 90 calculates the heat amount Hc generated by the heating element 30 based on the electric power W, the energization time Ti, and the integrated value of the current value I by using arithmetic expression.

In addition, the controller 90 counts the number of times of switching on/off the switching element 71, and calculates the heat amount Sc generated by the switching element 71 based on this count value by using arithmetic expression, a map or the like. The controller 90 calculates the outflow temperature T2 based on the inflow temperature T1, the heat amount Hc generated by the heating element 30, and the heat amount Sc generated by the switching element 71 using the following formula f1. In the formula f1, “c” represents a specific heat of water, and “q” represents a flow rate of water.

T2=T1+(Hc+Sc)/(c×q)  (f1)

The flow rate “q” of water may be a predetermined constant value, or a value detected from a flow rate sensor may be used as the flow rate “q” of water. Alternatively, information on the flow rate “q” of water may be acquired from a pump that supplies water to the electric heater device 10.

When the heat amount Sc generated by the switching element 71 is smaller than the heat amount Hc generated by the heating element 30, the controller 90 can calculate the outflow temperature T2 based on the following formula f2.

T2=T1+Hc/(c×q)  (f2)

According to the electric heater device 10 of the present embodiment, in addition to the above effects (1) and (2), the following effect (4) can be obtained.

(4) The inflow temperature T1 and the outflow temperature T2 can be obtained by merely providing one temperature sensor 72 in the electronic component module 70. Thus, it is possible to eliminate the temperature sensor 73 from the electronic component module 70, so that the number of components can be reduced, as compared with the structure in which two temperature sensors 72, 73 are provided in the electronic component module 70 as in the first embodiment.

Modifications

Next, a modification of the electric heater device 10 of the second embodiment will be described. The electronic component module 70 of this modification has only the temperature sensor 73 in place of the temperature sensor 72. The controller 90 detects the outflow temperature T2 based on the output signal of the temperature sensor 73 and calculates the inflow temperature T1 based on the following formula f3 or f4.

T1=T2−(Hc+Sc)/(c×q)  (f3)

T1=T2−Hc(c×q)  (f4)

It is possible to acquire information on the inflow temperature T1 and the outflow temperature T2 by merely providing one temperature sensor 73 in the electronic component module 70. Therefore, it is possible to eliminate the temperature sensor 72 from the electronic component module 70, as compared with the first embodiment in which two temperature sensors 72, 73 are provided in the electronic component module 70.

OTHER EMBODIMENTS

The respective embodiments can also be implemented in the following manners.

The electric heater device 10 may heat appropriate fluid other than water.

The units and/or functions provided by the controller 90 may be provided by software stored in a tangible storage device and a computer executing the software, hardware alone, or combinations of the software and the hardware. For instance, suppose cases that the controller 90 is provided with an electronic circuit serving as a hardware; such an electronic circuit may be provided with analog circuitry and/or digital circuitry including multiple logic circuits.

The present disclosure is not limited to the specific examples described above. The specific examples described above which have been appropriately modified in design by those skilled in the art are also encompassed in the scope of the present disclosure so far as the modified specific examples have the features of the present disclosure. Each element included in each of the specific examples described above, and the placement, condition, shape, and the like of the element are not limited to those illustrated, and can be modified as appropriate. The combinations of elements included in each of the above described specific examples can be appropriately modified as long as no technical inconsistency occurs. 

What is claimed is:
 1. An electric heater device comprising: a plurality of pipes stacked with each other through a predetermined clearance, a fluid flowing inside the plurality of pipes; a heating element that emits heat by being energized; and an electronic component module including an electronic component different from the heating element, wherein the heating element and the electronic component module are disposed in the clearance between the plurality of pipes.
 2. The electric heater device according to claim 1, wherein the electronic component includes a switching element of a driving circuit for the heating element.
 3. The electric heater device according to claim 1, wherein the electronic component includes a temperature sensor that detects temperature.
 4. The electric heater device according to claim 3, wherein the electronic component module and the pipe are in contact with each other at a first contact portion that is the most upstream in a flow direction of the fluid, the electronic component module and the pipe are in contact with each other at a second contact portion that is the most downstream in the flow direction of the fluid, and the electronic component module has a first temperature sensor disposed in the first contact portion and a second temperature sensor disposed in the second contact portion as the temperature sensor.
 5. The electric heater device according to claim 3, wherein the plurality of pipes includes a first pipe disposed to be in contact with only the electronic component module; and a second pipe positioned adjacent to the first pipe to be in contact with the electronic component module and the heating element, the electronic component module has a first contact portion in contact with the first pipe that is the most upstream side in a flow direction of the fluid flowing through the first pipe, and a second contact portion in contact with the second pipe that is the most downstream side in a flow direction of the fluid flowing through the second pipe, and the electronic component module has a first temperature sensor disposed in the first contact portion and a second temperature sensor disposed in the second contact portion as the temperature sensor.
 6. The electric heater device according to claim 3, wherein the temperature sensor detects one of an inflow temperature which is a temperature of the fluid flowing into a pipe stacked body defined by the plurality of pipes and an outflow temperature which is a temperature of the fluid flowing out of the pipe stacked body, and the electric heater device further comprises a calculator that calculates the other of the inflow temperature and the outflow temperature based on the temperature of the fluid detected by the temperature sensor.
 7. The electric heater device according to claim 6, wherein the calculator calculates the other of the inflow temperature and the outflow temperature based on a heat amount generated by the heating element and a flow rate of the fluid flowing through the pipe stacked body.
 8. The electric heater device according to claim 6, wherein the electronic component further includes a switching element of a driving circuit for the heating element, and the calculator calculates the other of the inflow temperature and the outflow temperature based on a heat amount generated by the heating element, a flow rate of the fluid flowing through the pipe stacked body, and a heat amount generated by the switching element. 